I'm sure some people here (pretre, AP, etc.) have read them already, but there are several (at least 4) battle reports floating around the intertubes now featuring Revenants. In the four I've read, the Revenants are barely scratched, but the Eldar player loses badly in each game. Seems the 900 points does indeed cripple the ability to field anything complementary that can stand up to a "more balanced" army selection. I was also intrigued that in Natfka's report his Void Shields pretty much nullified the Revenant and its Tau shooty allies. Sure, some lucky rolls (and unlucky rolls) were made, but the Shields did their job as described.
Anyway, I've found all the reports compelling and I am very excited to try out all these glorious new choices. Especially for my poor, outdated orkses!